ocfs2: use allocation reservations during file write

Add a per-inode reservations structure and pass it through to the
reservations code.

Signed-off-by: Mark Fasheh <mfasheh@suse.com>
diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index e6e8281..19d16f2 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -483,6 +483,9 @@
 
 	down_write(&OCFS2_I(inode)->ip_alloc_sem);
 
+	ocfs2_resv_discard(&osb->osb_la_resmap,
+			   &OCFS2_I(inode)->ip_la_data_resv);
+
 	/*
 	 * The inode lock forced other nodes to sync and drop their
 	 * pages, which (correctly) happens even if we have a truncate